Loud speaker



I 630, 4 May 1927' c. L. FARRAND ET AL 73 LOUD SPEAKER Filed Nov. 5, 1926 ATTORNEYS Patented May 31, 1927.

UNITED STATES PATEN T' OFFICE.

CLAIR L. FARRAND, FOREST HILLS, NEW YORK,

AND ERNEST ROSS, 01 EAST ORANGE, NEW JERSEY; SAID ROSS ASSIGNOR TO FARRAN D MFG. CO. IN (7., 0]? LONG ISLAND CITY, NEW YORK, A CORPORATION OF NEW JERSEY.

LOUD SPEAKER.

Application filed November This invention relates to loud speakers and particularly to that type which employs a large conical diaphragm.

Loud speakers of the cone type as heretofore constructed have included a conical diaon the line 22 of phragm, an actuating unit, and a driving rod connecting the actuating unit to the apex of the diaphragm. It has been customary to clamp the apex of the cone between small inner and outer metal caps or washers through which the extremity of the rod passes, and to secure the rod to these caps by means of a set screw. The diaph'ragms of cone speakers expand and contract considerably, due, among other things, to changes in weather conditions. The expansion and contraction of the diaphragm would give it an undesirable tension and perhaps change the adjustment of the actuating unit if some means were not employed to prevent or overcome this condition. The main advantageof the use of a set screw for clamping the cone to the driving rod resides in the fact that if the diaphragm expands or contracts, the set screw may be momentarily loosened to allow the actuating unit and diaphragm to readjust themselves and re'assume their original adjustments, after which the set screw is again tightened. Another advantage of the set screw is that it may be left in a loose condition during shipment of the loud speaker to break the positive connection between the cone and the driving rod so that the jaws to which the speaker is subjected during shipment are less likely to injure the actuating mechanism and the cone. However, the use of a set screw for this purpose has a number of disadvantages. For instance, it is easily lost, it is unsightly, and it constitutes a projection at the apex of the cone which entices persons to turn it bodily around the axis of the driving rod and thereby loosen the metal caps clamped to the apex of the cone.

The principal object of this invention is to provide a loud speaker having an improved type of connecting means at the junction of the driving rod and cone which possess the advantages of the set screw, but which is free of its disadvantages.

One form of the invention is illustrated in the accompanying drawings, in which 5, 1926. Serial No. 148,350.

Fig. 1 is a side elevation of a loud speaker having the improved connecting means between the drivmg rod and the apex of the cone.

Fig. 2 is an enlarged sectional view taken Fig. 1, and

Flg. 3 1s a detail view showing the clutch member which constitutes one element of the connecting means between the driving rod and the cone. The loud speaker illustrated in the drawmg is ofthat ty e ordinarily known as a double cone spea er, but the invention is applicable to any type of loud speaker where it (isdesirablbe to cennect the diaphragm with a rlvmg r0 b 0 am in means of the e hereinafter desd ribed. g typ The loud speaker illustrated in the draw- 1ng comprises a cone-shaped diaphragm 11.

and a frustum of a cone 2, the bases of the cone and the cone frustum beingunited, as by cementing them together. An ornamental cord 3 is placed around the structure so formed at the meeting edges of the cone 1 and cone frustum 2. The edge portion of the cone frustum 2 is held in a ring structure 4: supported by means of rods 5 passing downwardly through an opening in the lowermost portion of the cone structure to a base 6 to which they are secured. The rods 5 support an electrical actuating unit 3 which actuates the driving rod 8 referred to above A more detailed description of these parts 18 unnecessary as their construction is immaterial so far as the present invention 1s concerned.

It is the connection between the driving I is provided with a flange 9 and a threaded.

extremity 10. The threaded extremity 10 is inserted through a perforation 11 at the apex of the cone and a nut 12 threaded on to connection is the extremit 10 serves to clamp the clutch member to t e cone. Beforeattaching the clutch member to the cone inner and outer metal caps or washers 13 and 14 are up lied to the apex of the cone. These ca 5 ave central openin corresponding to t e perforation 11 in t e a ex of the cone to permit insertion through t em of the end portion 10 of the clutch member. When the nut 12 is tightened the apex of the cone, together with the metal caps 13 and 14 are clamped between the nut and the shoulder 9. The clutch member is provided with a central bore or opening 15 to receive the driving rod 8. The bore 15 is slightly larger in d1- ameter than the driving rod. That part of the clutch member to'the right of the flange 9 is threaded as shown at 16 to receive a collet 17. This portion of the clutch member is also rovided with one or more longitudinal s its 18 extending entirely across the width of the clutch member. In the present instance onl one of such slits is employed. It serves to Iifurcate the right hand end of the clutch member and to form two resilient jaws which ma be pressed inwardly toward the driving ro clutch member is tapered as shown at 19 and the collet 17 is provided with a tapered opening 20 adapted to cooperate with the tapered extremity on the clutch member in such a way that when the collet 17 is turned 1n a clockwise direction the resilient jaws of the clutch are wedged or forced inwardly into firm contact with the driving rod 8. This insures. a positive and tight connection be tween the drivin rod and the clutch memher and as the c utch member is ri idly attached to the cone, the tightening o the collet establishes a rigid connection from the driving rod to the cone. By turning the col let in the op osite direction, this positive broken, and therefore the collet may be manipulated to establish or break the connection between the driving rod and the cone thus accomplishing the same result as the above-mentioned set screw heretofore used. The outer surface of the collet 17 is preferably knurled as shown at 21 in Fig. 1, in order that a good grip may be obtained upon it. The collet constitutes convenient and easily manipulated means for momentarily breaking the connection between the driving rod and the cone when it is desired toallow the parts to readjust themselves after expansion or contraction .of the diaphragm has taken place. If desired, it

may be left in a loose condition during shipment of the speaker, to prevent jars from injuring either the actuating mecha- -nism or the cone. The collet causes the :peaker to present a much neater ap earance 11 when a set screw is employ ,Furthermore, its exterior surface is smooth, except for the knurling, and there are no pro- 8. The extreme end of the *jecting portions with their attendant dis- 1. A loud speaker comprising a diaphragm, actuating mechanism therefor including a driving rod, and connecting means between the driving rod and the diaphra comprising a clutch member secured to $2 a diaphragm having resilient jaws, and

collet cooperating with the clutch member adapted, when actuated, to forcethe resilient jaws of the clutch member into engagement with the driving rod.

2. A loud speaker comprising a; diaphragm, actuating mechanism therefor includmg a driving rod, and connecting means between the drivm rod and the dia hra com rising a clutc member secured to 5: d1ap ragm, said clutchv member having a central opening to receive the driving rod and a lurality of resilient jaws, a member movab e lon 'tudinally of the clutch member and means w ereby a longitudinal movement of said member causes said 'aws to move intio or out of engagement wit the driving ro 3. A loud speaker comprising a diaphragm, actuating mechanism therefor including a driving rod, and connecting means between the driving rod and the dia hra comprising a clutch member provide wit a shoulder and a threaded extension to one side at the shoulder, a nut cooperating with said threaded extension to clamp the diaphragm to said shoulder, said clutch memer having a central opening to receive said driving rod and bein provided at the opposite side of said s oulder with a longitudinal slit to form a lurality of resilient jaws, a collet having t readed en agement with said jaws, and said collet an resilient jaws having 'mterengaging inclined faces III o ening to receive the driving rod, said let causes said resilient jaws to move into 0 utch member having resilient aws extendor out of engagement with the driving rod. ing outwardly from the apex of the dia- In testimony whereof we afiix our signa- 10 phragm, a collet having threaded engagetures.

ment with said resilient jaws, and said resilient jaws and collet having interengaging in-' CLAIR L. FARRAND. clined surfaces whereby turning of the col- ERNEST ROSS. 

